<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div{
      position: absolute;
      width: 200px;
      height: 200px;
    }

    .box1{
      background-color: pink;
      z-index: 1;
    }

    .box2{
      background-color: skyblue;
      left: 100px;
      top: 100px;
      z-index: 2;
    }
    
  </style>
</head>
<body>
  <div class="box1">box1</div>
  <div class="box2">box2</div>
</body>
</html>